Bras and Breast Cancer
This email rumor states that wearing a bra for the whole day compresses the lymphatic system of the breast, resulting in accumulation of toxins that cause breast cancer. It says "Bra-burning is no longer a feminist issue...it is now a battle between life and death."
There are no scientifically valid studies that show wearing bras of any type causes breast cancer. The email appears to be based on the writings of a husband and wife team of medical anthropologists who link breast cancer to wearing a bra. The two anthropologists suggested this association in a book called Dressed to Kill. Their study was not conducted according to standard principles of epidemiological research and did not take into consideration other variables, including known risk factors for breast cancer.
We know of only one scientifically-conducted epidemiologic study that investigated a possible link between bra use and breast cancer. This study suggested that breast cancer might be less common among women who do not wear bras than among bra wearers. However, breast cancer risk in the two groups was not significantly different, according to standard statistical criteria, and the researchers themselves expressed uncertainty regarding this correlation. They also noted that if there is any connection, it would most likely have occurred indirectly, because women who are obese or have larger breasts are less likely to go braless. Obesity has been identified by numerous studies as a breast cancer risk factor, and having large breasts has been suggested in some studies as increasing breast cancer risk for young women who are not overweight.
We do not know of any epidemiologic studies published in scientific journals that suggest bras directly contribute to breast cancer risk or that lymphatic compression by bras might cause breast cancer.
Regardless of the size of a woman's breast and whether she is slim or heavy, there is no convincing epidemiologic evidence that her choices regarding bra use will influence her breast cancer risk. Furthermore, the alleged mechanism suggested in the book and in chain e-mails (blocked lymphatic vessels causing toxins to accumulate) is inconsistent with scientific concepts of breast physiology and pathology.